Opioid-dependent growth of glial cultures: suppression of astrocyte DNA synthesis by met-enkephalin.
The action of met-enkephalin on the growth of astrocytes in mixed-glial cultures was examined. Primary, mixed-glial cultures were isolated from 1 day-old mouse cerebral hemispheres and continuously treated with either basal growth media (controls), 1 microM met-enkephalin, 1 microM met-enkephalin plus the opioid antagonist naloxone (3 microM), or naloxone alone (3 microM). Absolute numbers of neural cells were counted in unstained preparations, while combined [3H]-thymidine autoradiography and glial fibrillary acid protein (GFAP) immunocytochemistry was performed to identify specific changes in astrocytes. When compared to control and naloxone treated cultures, met-enkephalin caused a significant decrease in both total cell numbers, and in [3H]-thymidine incorporation by GFAP-positive cells with flat morphology. These results indicate that met-enkephalin suppresses astrocyte growth in culture.
Stiene-Martin
A
A
Department of Anatomy and Neurobiology, University of Kentucky School of Medicine, Lexington 40536-0084.
Hauser
K F
KF
D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002452:Cell Count; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects*; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008813:Mice, Inbred ICR; D009457:Neuroglia / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; D004744:Enkephalin, Methionine; D004247:DNA; D013936:Thymidine